GPII-277: Create a Settings Handler for Android's Settings.System and Settings.Secure

This pull request brings us a new Settings Handler for Android, which deals with Android's native settings from Settings.System, Settings.Secure and Settings.Global. More information about it: 
* http://developer.android.com/reference/android/provider/Settings.System.html
* http://developer.android.com/reference/android/provider/Settings.Secure.html
* http://developer.android.com/reference/android/provider/Settings.Global.html

This pull request can be tested with https://github.com/GPII/universal/pull/154

Cheers,
Javi